Mrs Miggins, I did a lot of googling after my MMC, and within that googling came the question of can some women only carry one gender of babies. Now, I googled SOOOO much, that most of it is now a jumble in my head! There was a large amount of ladies out there asking the same question. There was some suggestions that it is not a case of not being able to carry a boy, but that boys are actually a little more fragile as unborns than girls. It was just one statistic study that suggested this, and it only suggested it lightly- there was just a really small difference in survival between girls and boys and the study was quite small. I shall go googling again now, and try to find if there is an actual recognized condition/cause that may lead women to not be able to carry boys.
In my opinion, if there is such a factor leading to some women not being able to carry boys it is probably so rare that you have a higher chance of winning the lottery 3 times in a row than actually being unable to carry boys.
I think its very common for ladies who have had a baby or babies of one gender then 2 or more losses after or inbetween to start to wonder if they can only carry that gender. We want to know so badly what caused our losses, that its only natural to explore every possibility.
*puts google hat on* be back in a bit!